README-sanitize-inline-keyword.md

sanitize-inline-keyword

This check prints a warning if a member method, in an exported class (i.e. a class with visibility attribute default), has the inline keyword on the definition but not the declaration. While this code will typically compile, certain compilers (e.g. MinGW) may show a warning in such cases, e.g.:

method redeclared without dllimport attribute after being referenced with dll linkage [-Werror]

At the time of writing this (2023-08-27), there is no easy way to suppress this warning, and if warnings are treated as errors, the whole build can fail (e.g. on CI systems).

The fix is simple, the inline keyword should be specificed for the declaration in-class, and not the definition.

For more details see this thread on the Qt Development mailing list.

This check has a fixit that adds the inline keyword to the declaration, and removes it from definition.

This check supports ignoring included files (i.e. only emit warnings for the current file), when run via clazy-standalone. If you plan on using the fixits of this check, it's recommended to use the --ignore-included-files option, to avoid having duplicate fixes (which may result in the inline keyword being added more than once to the same method).

Limitations

• Removing the inline keyword from the definition leaves an extra space character, however clang-format can easily take care of that
• This check doesn't show a warning for constexpr methods or function templates, because both are implicitly inline, so it wouldn't cause the aformentioned problem

Example

// Exported/visible class
class __attribute__((visibility("default"))) MyClass
{
    int a() const;
};

inline int MyClass::a() const
{
    ....
}